Use differentials to find the approximate amount of copper used in the four sides and bottom of a rectangular copper tank that is 6 feet long, 4 feet wide and 3 feet deep inside if the sheet of copper...

an airplane is heading 040degree with an airspeed of 800 km/h. A wind from the west causes it to have the course 045 degree. Find the resultant ground speed of the airplane and the speed of the wind...